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Changes in transcription pattern lead to a marked decrease in COX, CS and SQR activity after the developmental point
H Kolarova1, J Krizova, M Hulkova
1Department of Pediatrics and Adolescent Medicine, First Faculty of Medicine, Charles University and General University Hospital in Prague, Prague, Czech Republic. marketa.tesarova@lf1.cuni.cz.
Physiological Research
|November 16, 2017
Summary
Fetal liver and muscle tissue show decreasing oxidative phosphorylation (OXPHOS) enzyme activity after 22 weeks gestation, despite rising mitochondrial DNA transcription. This may impact infant survival.
Area of Science:
- Biochemistry
- Developmental Biology
- Cellular Respiration
Background:
- Fetal development involves complex cellular changes, including shifts in oxidative phosphorylation (OXPHOS).
- Previous data indicated increased COX4 and MTATP6 liver transcription after 22 weeks gestational age (GW).
Purpose of the Study:
- To investigate the functional impact of observed changes in OXPHOS gene expression during fetal development.
- To analyze specific OXPHOS enzyme activities and mitochondrial DNA (mtDNA) content in fetal liver and skeletal muscle.
Main Methods:
- Spectrophotometry and RT-PCR were used to measure COX, CS, SQR activities, and mtDNA content.
- Liver and skeletal muscle samples from 13-29 GW were analyzed.
- Liver hematopoiesis (LH) was assessed via light microscopy.
Main Results:
- mtDNA content correlated with gestational age in the liver only.
- COX, CS, and SQR activities significantly decreased in both liver and muscle mitochondria after 22 GW.
- Liver hematopoiesis declined from 14-24 GW, independent of OXPHOS activity.
Conclusions:
- Decreasing OXPHOS activity alongside increasing mtDNA transcription appears crucial for neonatal adaptation.
- Impaired mitochondrial energy production capacity may contribute to mortality in infants born before 22 GW.
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